Physics of Sounds: Acoustics, Phonetics, Musical Notation, and Sound Waves, Study notes of Speech-Language Pathology

Download Physics of Sounds: Acoustics, Phonetics, Musical Notation, and Sound Waves and more Study notes Speech-Language Pathology in PDF only on Docsity! Descriptions of Sounds Three Standard Descriptions -Acoustics: the physical properties of sounds are precisely (numerically) described on paper or computer screens. Uses the language of physicals and is detailed - Phonetics: graphical coding of human speech with specialized symbols (phonetic alphabet) that describes the nuances of the sounds produced - Musical Notation: Permits the representation of certain sounds possessing “musical” features Attack, Body and Decay -Attack: the onset portion of the sound object. Sometimes called the “excitation” phase. In physics terminology, it is in this phase that energy is first put into the sound. When the sound first beings, there is a rough edge to it- the attack. The more sudden the attack- the more roughness that is present -Body: the middle portion of the sound that may seem unchanging or unprogressive. Many sounds may not have any body e.g. bells, cymbals, percussion -Decay: the portion of the sound object where it dies out or is terminated. The sound becomes weaker and weaker until it is gone. Some sounds decay rapidly, others slowly. Types of Information -Interaction of materials: materials that make up the car(steel, plastic, rubber) vibrate and in turn vibrate the air around it -Location: as sound waves travel through the air, they lose energy, especially at high frequencies. This can provide information about how far away we are from the source of sound. -Environment: the sound waves that travel from our car to our ears will reflect off various objects in the environment around it. Categories of Material Interaction -Vibration solids (closing a door, scraping fingernails across a chalkboard, footsteps) -Changes to the surface of a body of liquid (water droplets falling into a pool) -Aerodynamic (changes in the pressure of gases) (whistle, exploding balloon, leaky tire) Material Properties and Forces Fundamental Physical Quantities -Length: any measurement of distance is quantified by a length measurement -Mass: the amount of matter present mass does NOT equal weight -Time: may be in seconds, milliseconds, microseconds etc. Derived Quantities -Area- length times width -Displacement: a change in position. Involves both distance and direction -Velocity: is a distance traveled in a certain amount of time (and in a particular direction) -Acceleration: a measure of the change in velocity over time and is given in meters per second Material Properties -Mass: the amount of matter that is present. A mass in motion possesses inertia (a force that wants to maintain motion) -Elasticity: (stiffness, springiness): a material property that resists being deformed or moved away from a position of rest (a basketball resists being deformed, a ball of clay does not) When a material with elasticity is deformed it creates a force that “wants” to restore the material to its original shape. This force is called a restoring force. Material PropertyForce: Elasticity (stiffness) Restoring Force Material PropertyForce: MassInertial Force Friction between objects and within an objectconsumes energy and causes vibration to decay -Friction: opposes motion between the surface of an object and whatever it happens to be resting on -Potential Energy: stored energy that can be returned at some later time. Elasticity may be thought of as the ability of a substance to store potential energy. (stretching a rubber band) -Kinetic Energy: the energy of motion. Inertia can be thought of as the ability to store kinetic energy. Motion. (release of rubber band) Tuning Fork as a Vibrating System Four Phases (inertia- away from the middle, elasticity- back to the middle, friction effects amplitude not frequency) 1) Deflecting of the arm (mass) moves it away from its desired rest position. But a restoring force is generated by the stiffness 2) The restoring force (stiffness) brings the arm (mass) back to the rest position 3) At this point, the arm (mass) is moving very fast which means there is a large amount of inertia. The inertia forces the arm to move through the rest position. As it continues to move right to restoring force due to the stiffness is again generated, but now in the opposite direction. 4) Now the restoring force pushes the arm back toward the rest position. But, because of the inertia the arm will again move through the rest position and the whole process beings again. K M  F K M F